Electrical devices from polymer resins prepared with ionic catalysts

ABSTRACT

This invention relates to olefin polymers particularly suited to satisfying the dielectric properties required in electrical device use. The olefin polymers can be prepared by contacting polymerizable olefin monomers with catalyst complexes of Group 3-11 metal cations and noncoordinating or weakly coordinating anion compounds bound directly to the surfaces of finely divided substrate particles or to polymer chains capable of effective suspension or solvation in polymerization solvents or diluents under solution polymerization conditions. Thus, the invention includes polyolefin products prepared by the invention processes, particularly ethylene-containing copolymers, having insignificant levels of mobile, negatively charged particles as detectable by Time of Flight SIMS.

This Application is based on Provisional Application U.S. Ser. No.60/172,737 filed Dec. 20, 1999.

TECHNICAL FIELD

This invention relates to polymeric products that are particularlyuseful for electrical devices and to olefin polymerization processesthat use supported catalyst compounds where the catalysts are attachedto support materials.

BACKGROUND

Common examples of electrical devices include wire and cableapplications. Typical power cables include one or more electricalconductors in a core that is surrounded by several layers that caninclude a polymeric semi-conducting shield layer, a polymeric insulatinglayer and another polymeric semi-conducting shield layer, a metallictape, and a polymeric jacket. Thus, a wide variety of polymericmaterials have been used as electrical insulating and semi-conductingshield materials for wire, cable, and numerous other electricalapplications.

Polymerized elastomer or elastomer-like polymers are often used in powercables. Ethylene, C₃-C₁₂ α-olefin, and C₅-C₂₀ non-conjugated dienemonomers form these elastic materials. Polymers containing ethylene,either homopolymers or copolymers with C₃-C₂₀, olefinically unsaturatedcomonomers, are also used as insulating layers or semiconducting layers.See for example, U.S. Pat. Nos. 5,246,783, 5,763,533, InternationalPublication WO 93/04486, and generally, “Electric Insulation”,Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed., pages 627-647(John Wiley & Sons, 1993). Dielectric strength, electrical resistivity,electrical conductivity, and dielectric constant are all importantcharacteristics for these applications.

Polymerization of olefinically unsaturated monomers is well known andhas led to the proliferation of elastomeric and plastic materials, suchas polyethylene, polypropylene, and ethylene-propylene rubber. Catalystcompounds with bulky, stabilizing-ligand-containing metal cationcomponents are now well known in the art. Examples includecyclopentadienyl-ligand-containing transition metal compounds (e.g.,metallocenes), bisamido- and bisimido-ligand-containing transition metalcompounds, as well as other metal compounds that are stabilized byincorporating bulky ligands. Cocatalyst compounds containing, or capableof providing, non-coordinating anions can be used to stabilize thetransition metal cations and maintain their cationic form rendering themsuitable for olefin oligomerization and polymerization, see for exampleU.S. Pat. No. 5,198,401. This and related references describemetallocene compound protonation by anion precursors to form stablecatalysts.

U.S. Pat. Nos. 5,427,991, and 5,643,847 specifically teach the use ofanionic complexes directly bound to supports through chemical linkagesto improve polymerization processes that are conducted under slurry orgas-phase polymerization conditions. See also U.S. Pat. No. 5,939,347which addresses protonating or abstracting cocatalyst activators boundto silica.

Low crystallinity ethylene-containing elastomers and ethylene-containingpolymers can be produced under gas-phase or slurry conditions, but aremore typically prepared by solution polymerization processes, in partbecause these polymers have good solubility in commonly used hydrocarbylsolvents see the supported-catalyst references cited above. Examplesinclude: U.S. Pat. Nos. 5,198,401 (above), 5,278,272, 5,408,017,5,696,213, 5,767,208 and 5,837,787; and, EP 0 612 678, EP 0 612 679,International Applications WO 99/45040 and WO99/45041. Although eachreference, in part, addresses ethylene-containing polymers prepared withionic catalyst compounds; preparing satisfactory electrical devicepolymers from these solution processes has unsolved problems. Usingnoncoordinating or weakly coordinating anion cocatalyst complexes posesa problem because it leaves labile, anionic-charge-carrying species as abyproduct within the resulting polymeric resins or matrices. Thesemobile anions adversely affect both dielectric strength and dielectricconstant.

Additionally, olefin solution polymerization processes are generallyconducted in aliphatic solvents that serve both to maintain reactiontemperatures and solvate the polymer products. But aryl-group-containingcatalysts, those having cyclopentadienyl derivatives and other fused orpendant aryl-group substituents, are sparingly soluble in such solventsand typically are introduced in the aryl solvents such as toluene.Because of health concerns, the aryl solvent must be removed. Also, arylsolvents reduce process efficiencies making their presence undesirable.Alternatively, relatively insoluble catalysts can be introduced usingslurry methods, but such methods required specialized handling andpumping procedures that complicate industrial scale plant design and addsignificant costs to plant operation. Typical slurry compositions causesignificant wear on pumps, piping, joints, and connectors. Lowsolubility also poses a problem when the processes involve lowtemperature operation at some stage such as typically seen in adiabaticprocesses run in colder climates. The adiabatic reactor is operated atambient temperature. Thus, the catalyst's low solubility is furtherlowered by a colder reaction temperature. Additionally, counteractingthe build-up of aryl solvents in the recycle system, or separating themfrom the system, presents added problems. At the same time, maintaininghigh molecular weights in olefin polymers while operating ateconomically preferable high reaction temperatures and high productionrates is highly desirable.

INVENTION DISCLOSURE

In part, this invention is a method for preparing olefin polymers. Themethod includes contacting olefin monomers with a catalyst systemcontaining Group-3 to -11 metal-cation complexes that are surface boundto a substrate. The substrate is finely divided particles that can beeffectively suspended in or solvated by reaction solvents or diluents.Thus, the invention, in part, relates to a process for preparingolefin-polymerization-catalyst compositions that contain particulate orpolymeric support material connected to the catalyst activator and aGroup 3-11, metal-catalyst-precursor compound that can be activated forolefin polymerization. One goal is to substantially immobilize theactivator so that after activation, the resulting non-coordinating anionand the catalyst are trapped within the substrate. Another goal is tomodify the catalyst system so that it is soluble in the aliphaticpolymerization solvent, or if not soluble, suspendable in the solventsuch that the abrasive effect (as well as other negative effects facedin slurry polymerization) is substantially eradicated. This is done toprevent ion-based conduction in the resulting polymer. Additionally, theinvention includes the polymer products prepared by the inventionprocesses, particularly ethylene-containing polymers havinginsignificant levels of mobile, negatively charged particles asdetectable by Time-of-Flight SIMS spectra.

Furthermore, the inventor also relates to the cocatalyst and catalystsystem compositions using support-bound cocatalysts.

DETAILED DESCRIPTION AND EXAMPLES OF THE INVENTION

The advantages of olefin solution polymerization generally, and ethylenepolymerization particularly, can be effectively extended by use of theinvention process. The suspended, supported catalysts will meet thesolution process requirements of pumpability and dispersability in thepolymerization medium. Thus, the high activities or productivitiesenabled by systems based on aryl-group-containing catalysts andcocatalysts can be readily achieved without leaving noncoordinating orweakly coordinating anion residue in the polymer resins. Additionally,difficulties associated with using bulky-ligand-containing,organometallic, catalyst and cocatalyst activator compounds in which thepresence of aryl- and haloaryl-group ligands (such as, phenyl,perfluorophenyl, napthyl, perfluoronapthyl, cyclopentadienyl, indenyl,fluorenyl, etc.) inhibit aliphatic solvent solubility can be overcomeusing the invention's supported catalyst and cocatalyst compoundsbecause the compounds are easily suspendable in aliphatic solvents.

Description of Support Materials

Support material suitable for use with the invention can be any of theinorganic oxide or polymeric support materials that 1) have, or can betreated to have, reactive functional groups for connecting or chemicallybinding the catalyst or cocatalyst and 2) are small enough orconstitutes such that they disperse or dissolve in aliphatic solvents.Some embodiments include finely divided substrate particles that areessentially colloidal in size, or more quantitatively, less than orequal to about 2 microns, and are substantially non-porous. Theparticles can be essentially pore-free since reaction exotherm controldepends more on the presence of the solution processes' solvent ordiluent.

Suitable support materials include commercially available pyrogenicsilicas, commonly called fumed silicas. A typical silica preparationprocess uses vapor-phase hydrolysis of silicon tetrachloride at around1000° C. Other methods include SiO₂ vaporization, Si vaporization andoxidation, and high temperature oxidation and hydrolysis of siliconcompounds such as silicate esters. Examples include the Aerosil™ andCab-O-Sil™ of Degussa and Cabot Corp. respectively. Even after hightemperature preparation, these silica products retain enough silanolgroups to connect with the cocatalyst precursor. The silanol groups arenucleophilic. It is believed that they react with the Lewis-acidic,cocatalyst precursors, such as trisperfluorophenyl borane. Furthermore,the particles' near-colloidal size permits dispersion in polymerizationsolvents and diluents, even after treatment with cocatalyst precursorcompounds. In some embodiments, the treated particles form colloidalsuspensions in aliphatic polymerization, or other compatible, solvents.Additional support materials include metal or metalloid compounds, suchas oxides, that comprise significant amounts ofhydroxyl-group-containing silica or silica equivalent. Examples includealumina, alumino-silicates, clays, talcs, or other silica-containingGroup-14 metalloid-metal element compounds. R. P. H. Chang, J. M.Lauerhaus, T. J. Marks, U. C. Pernisz, “Silica Nanoparticles ObtainedFrom a Method Involving a Direct Current Electric Arc in anOxygen-Containing Atmosphere”, U.S. Pat. No. 5,962,132, Oct. 5, 1999,describes methods of preparing silica particles of less than 100 nmdiameter. This patent is incorporated by reference for the purposes ofU.S. Patent Practice.

In some embodiments, polymeric supports include polystyrene gels orbeads having a 2 micron or less mesh size. It is believed that internalspores are unnecessary in some embodiments because the catalyst orcocatalyst attaches to the bead or gel surface materials. Thesolution-based polymerization conditions help to eliminate particle sizeconcerns seen in typical gas phase or slurry polymerizations. Thus, insome embodiments, the surface area is less than about 300 m²/g, evenless than 200 m²/g as measured by single point nitrogen B.E.T. analysis(Brunauer, S., Emmett, P. H., Teller, E., JACS 1938, 60, 309). Thecocatalyst precursors can be attached using any means that permitsubstantial connection to the substrate. See for instance U.S. Pat. Nos.5,427,991, 5,643,847, 5,939,347, WO 98/55518 and co-pending U.S.application Ser. No. 09/351,983 filed Jul. 12, 1999 (Atty. Docket No.98B041) now abandoned. Each is incorporated by reference for purposes ofU.S. patent practice.

Additional support materials include the essentially amorphous orsemicrystalline aliphatic-solvent-soluble polyolefins, for example,ethylene-containing polymers that contain nucleophilic groups forreacting with Lewis acid cocatalyst precursors. Various means ofincorporating nucleophilic groups into these polymers such that theyreact with the Lewis acidic precursors are known in the art. See, U.S.Pat. Nos. 5,153,282, 5,427,991, and WO 98/55518. Some polymerembodiments, such as those from ethylene, α-olefin monomers, oroptionally containing non-conjugated diolefin comonomers grafted withmaleic anhydride, are suitable. After the treatment with the cocatalystor after reaction with transition metal catalyst precursor, thesubstrate polymer should be readily dispersible or dissolvable. Thismeans that the untreated substrate should contain little enoughcrosslinking so that it remains soluble or dispersible in thepolymerization solvent after treatment with the cocatalyst or catalystprecursor.

The silica-based support can be fluorinated after dehydration todecrease the number of catalyst-degrading, surface functionalities.Suitable fluoridating compounds are typically inorganic. They may be anythat contain fluorine as long as they do not contain a carbon atom. Someembodiments use inorganic fluorine-containing compounds such as NH₄BF₄,(NH₄)₂SiF₆, NH₄PF₆, NH₄F, (NH₄)₂TaF₇, NH₄NbF₄, (NH₄)₂GeF₆, (NH₄)₂SmF₆,(NH₄)₂TiF₆, (NH₄)₂ZrF₆, MoF₆, ReF₆, GaF₃, SO₂ClF, F₂, SiF₄, SF₆, ClF₃,ClF₅, BrF₅, IF₇, NF₃, HF, BF₃, NHF₂, and NH₄HF₂. Of these, ammoniumhexafluorosilicate and ammonium tetrafluoroborate are particularlyuseful.

Ammonium hexafluorosilicate and ammonium tetrafluoroborate fluorinecompounds are typically solid particulates. A desirable method oftreating the support with the fluorine compound is to dry mix the twocomponents by simply blending at a concentration of from 0.01 to 10.0millimole F/g of support, desirably in the range of from 0.05 to 6.0millimole F/g of support, and most desirably in the range of from 0.1 to3.0 millimole F/g of support. The fluorine compound can be dry mixedwith the support either before or after their addition to support,dehydration, or calcination vessels. Accordingly, the fluorineconcentration present on the support is in the range of from 0.6 to 3.5wt % of support.

In another method, the fluorine is dissolved in a solvent such as waterand then the support is contacted with the fluorine-containing solution.When water is used and silica is the support, it is desirable to use aquantity of water that is less than the total pore volume of thesupport.

Silica dehydration or calcination is not necessary before reacting itwith the fluorine compounds. Desirably, the reaction between the silicaand fluorine compound is carried out at a temperature of from about 100°C. to about 1000° C., and more desirably from about 200° C. to about600° C. for about two to eight hours.

The term noncoordinating anion as used for the invention compounds isart-recognized to mean an anion that either does not coordinate to thetransition metal cation or that coordinates weakly enough to bedisplaced by a neutral Lewis base. “Compatible” noncoordinating anions(NCA) are those which are not neutralized when reacted with the catalystprecursor compounds. Further, the compatible anion should not transferanionic substituents or fragments to the catalyst to form a neutralmetal compound and a neutral NCA by-product. Noncoordinating anionsuseful with invention embodiments are those that are compatible with orstabilize the invention transition metal cation by balancing its ioniccharge, yet can be displaced by an olefinically unsaturated monomerduring polymerization. Additionally, because the anions are supportbound, it is believed that they have sufficient size to inhibit orprevent neutralization of the invention catalysts by any extraneousLewis bases present in the reaction. Suitable aryl ligands for theinvention include those of the noncoordinating anions as described inU.S. Pat. Nos. 5,198,401, 5,278,119, 5,407,884, and 5,599,761. Specificexamples include the phenyl, napthyl, and anthracenyl radicals of U.S.Pat. No. 5,198,401, the biphenyl radicals of WO 97/29845, and theligands of the noncoordinating anions of WO 99/45042, preferably where amajority of ring-hydrogen atoms are replaced with halogens. Alldocuments are incorporated by reference for purposes of U.S. patentpractice. In some embodiments, the anions' sources are neutral,tri-coordinate Lewis acids that contain aryl-substituted boron oraluminum, and that are reactive with the support material's nucleophilicgroups, e.g., hydroxyl groups of the fumed silica or polymer substrate.Trisperfluorophenyl borate, trisperfluoronapthylborate, andtrisperfluorobiphenylborate are examples.

Invention, supported catalysts can be prepared by adding organometallic,transition-metal catalyst-precursor compounds into a well-stirred orwell-mixed solution or suspension of the fine-particle- orpolymeric-supported cocatalysts long enough to allow the cocatalyst toionize the catalyst precursor into cationic catalysts. The catalyst andcocatalyst reaction can be conducted at ambient temperature or can bewarmed to 40° C. or higher to facilitate the reaction. The reactionproduct is a catalytic, cationic metal complex connected to thesupport-bound noncoordinating or weakly coordinating anion. Thecatalyst-cocatalyst complex can then be directly added into a reactor,or can be dried or separated from the suspension for subsequentpolymerization.

Transition metal compounds suitable as polymerization catalysts inaccordance with the invention include the known transition metalcompounds useful in traditional Ziegler-Natta polymerization and as wellthe metallocene compounds similarly known to be useful inpolymerization. The compounds are suitable when the invention cocatalystactivators can catalytically activate them. These typically includeGroup-3-11 transition metal compounds in which at least one metal ligandcan be protonated by the cocatalyst activators, particularly thoseligands including hydride, alkyl, and silyl, and lower alkyl-substituted(C₁-C₁₀) silyl or alkyl derivatives of those. Ligands capable ofabstraction and transition metal compounds comprising them include thosedescribed in the background art, see for example U.S. Pat. No. 5,198,401and WO 92/00333. Syntheses of these compounds are well known from thepublished literature. Additionally, where the metal ligands includehalide, amido, or alkoxy moieties (for example, biscyclopentadienylzirconium dichloride) that the invention cocatalysts can't abstract, themoieties can be converted into suitable ligands through known alkylationreactions with lithium or aluminum hydrides or alkyls, alkylalumoxanes,Grignard reagents, etc. See also EP-A1-0 570 982 for organoaluminumcompounds reaction with dihalo-substituted metallocene compounds beforeadding an activator. All documents are incorporated by reference forpurposes of U.S. patent practice.

Additional description of metallocene compounds that comprise, or can bealkylated to comprise, at least one ligand capable of abstraction toform a catalytically active transition metal cation appear in the patentliterature, e.g., EP-A-0 129 368, U.S. Pat. Nos. 4,871,705, 4,937,299,5,324,800 EP-A-0 418 044, EP-A-0 591 756, WO-A-92/00333, WO-A-94/01471and WO 97/22635. Such metallocene compounds are mono- orbiscyclopentadienyl-substituted Group-3, -4, -5, or -6 transition metalcompounds in which the ligands may themselves be substituted with one ormore groups or may bridge to each other or to the transition metalthrough a heteroatom. The size and constituency of the ligands andbridging elements are not critical to preparing the invention catalystsystems, but should be selected in the literature-described manner toenhance the desired polymerization activity and polymer characteristics.In some embodiments, the cyclopentadienyl rings (including substitutedcyclopentadienyl-based fused-ring systems, such as indenyl, fluorenyl,azulenyl, or their substituted analogs), when bridged to each other,will be lower-alkyl-substituted (C₁-C₆) in the 2 position (with orwithout a similar 4-position substituent in the fused-ring systems) andmay additionally comprise alkyl, cycloalkyl, aryl, alkylaryl, orarylalkyl substituents, the latter as linear, branched, or cyclicstructures including multi-ring structures, for example, those of U.S.Pat. Nos. 5,278,264 and 5,304,614. Such substituents should each haveessentially hydrocarbyl characteristics and will typically contain up to30 carbon atoms, but may be heteroatom-containing with 1-5 non-hydrogenor carbon atoms, e.g., N, S, O, P, Ge, B and Si. All documents areincorporated by reference for purposes of U.S. patent practice.

Metallocene compounds suitable for the preparation of linearpolyethylene or ethylene-containing polymers (where copolymer meansformed from at least two different monomers; for this disclosure,“polymer” completely encompasses all varieties of homo-, hetero,copolymers) are essentially any of those known in the art, see againWO-A-92/00333 and U.S. Pat. Nos. 5,001,205, 5,198,401, 5,324,800,5,304,614 and 5,308,816, for specific listings. Selection of metallocenecompounds for use to make isotactic or syndiotactic polypropylene, andtheir syntheses, are well-known in both the patent and academicliterature, see for example Journal of Organometallic Chemistry, 369,359-370 (1989). Typically, those catalysts are stereorigid, asymmetric,chiral, or bridged-chiral metallocenes. See, for example, U.S. Pat. No.4,892,851, U.S. Pat. No. 5,017,714, U.S. Pat. No. 5,296,434, U.S. Pat.No. 5,278,264, WO-A-(PCT/US92/10066) WO-A-93/19103, EP-A2-0 577 581,EP-A1-0 578 838, and academic literature “The Influence of AromaticSubstituents on the Polymerization Behavior of Bridged ZirconoceneCatalysts”, Spaleck, W., et al, Organometallics 1994, 13, 954-963, and“ansa-Zirconocene Polymerization Catalysts with Annelated RingLigands-Effects on Catalytic Activity and Polymer Chain Lengths”,Brinzinger, H., et al, Organometallics 1994, 13, 964-970, and documentsreferred to in the references. Although these references are directed tocatalyst systems with alumoxane activators, some analogous precursorswill be useful with invention cocatalyst activators. A suitable catalystprecursor typically has 1) one or more ligands that have been replacedwith an abstractable ligand; and 2) one or more ligands into which anethylene group, —C═C—, can insert. Examples include hydride, alkyl, orsilyl. All documents are incorporated by reference for purposes of U.S.patent practice.

Some representative metallocene compounds have the formula:

L^(A)L^(B)L^(C) _(i)MDE

where, L^(A) is a substituted cyclopentadienyl or heterocyclopentadienylligand connected to M; L^(B) is a member of the class of ligands definedfor L_(A), or is J, a heteroatom ligand connected to M; the L^(A) andL^(B) ligands may be connected together through a Group-14-elementlinking group; L^(C) _(i) is an optional neutral, non-oxidizing ligandconnected to M (i equals 0 to 3); M is a Group-4 or -5 transition metal;and, D and E are independently monoanionic labile ligands, eachconnected to M, optionally connected to each other or L^(A) or L^(B), inwhich the connection can be broken by a suitable activator and intowhich a monomer or macromonomer can insert for polymerization.

Non-limiting representative metallocene compounds includemono-cyclopentadienyl compounds such aspentamethylcyclopentadienyltitanium isopropoxide,pentamethylcyclopentadienyltribenzyl titanium,μ-dimethylsilyltetramethylcyclopenta-dienyl-tert-butylamido titaniumdichloride, pentamethylcyclopentadienyl titanium trimethyl,dimethylsilyltetramethylcyclopenta-dienyl-tert-butylamido zirconiumdimethyl, dimethylsilyltetramethylcyclopentadienyl-dodecylamido hafniumdihydride, dimethylsilyltetramethylcyclopentadienyl-dodecylamido hafniumdimethyl, unbridged biscyclopentadienyl compounds such as bis(1,3-butyl,methylcyclopentadienyl) zirconium dimethyl,pentamethylcyclopentadienyl-cyclopentadienyl zirconium dimethyl,(tetramethylcyclopentadienyl)(n-propyl-cyclopentadienyl)zirconiumdimethyl; bridged bis-cyclopentadienyl compounds such asdimethylsilylbis(tetrahydroindenyl) zirconium dichloride andsilacyclobutyl(tetramethylcyclopentadienyl)(n-propyl-cyclopentadienyl)zirconium dimethyl; bridged bis-indenyl compounds such asdimethylsily-bisindenyl zirconium dichloride, dimethylsily-bisindenylhafnium dimethyl, dimethylsilylbis(2-methylbenzindenyl) zirconiumdichloride, dimethylsilylbis(2-methylbenzindenyl) zirconium dimethyl;and fluorenyl ligand-containing compounds, e.g.,diphenylmethyl(fluorenyl)(cyclopentadienyl)zirconium dimethyl; and theadditional mono- and biscyclopentadienyl compounds such as those listedand described in U.S. Pat. Nos. 5,017,714, 5,324,800 and EP-A-0 591 756.All documents are incorporated by reference for purposes of U.S. patentpractice.

Representative traditional Ziegler-Natta transition metal compoundsinclude tetrabenzyl zirconium, tetra bis(trimethylsilylmethyl)zirconium, oxotris(trimethylsilylmethyl) vanadium, tetrabenzyl hafnium,tetrabenzyl titanium, bis(hexamethyl disilazido)dimethyl titanium,tris(trimethyl silyl methyl) niobium dichloride,tris(trimethylsilylmethyl) tantalum dichloride. The important featuresof such compositions for polymerization are the ligands capable ofabstraction and the ligands into which the ethylene (olefinic) group caninsert. These features enable ligand abstraction from the transitionmetal compound and the concomitant formation of the invention ioniccatalyst compositions.

Additional transition metal polymerization catalysts in accordance withthe invention will be any of those Group-3-10 compounds that can beconverted by ligand abstraction into a catalytically active cation andstabilized in that state by a noncoordinating or weakly coordinatinganion, as defined above.

Exemplary compounds include those described in the patent literature.International patent publications WO 96/23010, WO 97/48735 and Gibson,et. al., Chem. Comm., pp. 849-850 (1998), disclose diimine-based ligandsfor Group 8-10 metal compounds shown to be suitable for ionic activationand olefin polymerization. See also WO 97/48735. Transition-metalcatalyst systems from Group 5-10 metals in which the active transitionmetal center is in a high oxidation state and stabilized by lowcoordination number, polyanionic ancillary ligand systems are describedin U.S. Pat. No. 5,502,124 and its divisional U.S. Pat. No. 5,504,049.See also the Group-5 organometallic catalyst compounds of U.S. Pat. No.5,851,945 and the tridentate-ligand-containing, Group 4-9 organometalliccatalyst compounds of copending U.S. application Ser. No. 09/302243,filed Apr. 29, 1999, now U.S. Pat No. 6,294,495 and its equivalentPCT/US99/09306. Group-11 catalyst precursor compounds, activated withionizing cocatalysts, and useful for polymerizing of olefins andvinyl-group-containing polar monomers are described and exemplified inWO 99/30822 and its priority document, including U.S. Pat. No.application Ser. No. 08/991,160, filed Dec. 16, 1997 now abandoned. Eachof these documents is incorporated by reference for the purposes of U.S.patent practice.

U.S. Pat. No. 5,318,935 describes bridged and unbridged bisamidotransition-metal compounds of Group-4 for olefin polymerizationcatalysts are described by D. H. McConville, et al, in Organometallics1995, 14, 5478-5480. Further work appearing in D. H. McConville, et al,Macromolecules, 1996, 29, 5241-5243, described bridged bis(arylamido)Group-4 compounds that are active catalysts for polymerization of1-hexene. See also WO 98/37109. Additional transition metal compoundssuitable for invention embodiments include those described in WO96/40805. Cationic Group-3 or Lanthanide metal complexes for olefinpolymerization are disclosed in copending U.S. application Ser. No.09/408050, filed Sep. 29, 1999 (Atty. Docket No. 98B054) now U.S. Pat.No. 6,403,773, and its equivalent PCT/US99/22690. The precursorcompounds are stabilized by monoanionic bidentate ligands and twomonoanionic ligands. Invention cocatalysts can activate these precursorcompounds. Each of these documents is incorporated by reference for thepurposes of U.S. patent practice.

Additional catalyst precursors are described in the literature, any ofwhich are suitable where they contain, or can be modified to contain,ligands capable of being abstracted for ionization of the organometalliccompounds. See, for instance, V. C. Gibson, et al, “The Search forNew-Generation Olefin Polymerization Catalysts: Life BeyondMetallocenes”, Angew. Chem. Int. Ed., 38, 428-447 (1999), incorporatedby reference for the purposes of U.S. patent practice.

When using the invention catalysts, particularly when they are supportbound, the total catalyst system will optionally contain one or morescavenging compounds. The term “scavenging compounds” as used in thisapplication includes compounds that remove polar impurities (catalystpoisons) from the reaction environment. Impurities can be introducedwith the reaction components, particularly solvent, monomer, andcatalyst feeds. These impurities vitiate catalyst activity andstability, particularly when ionizing-anion-precursors activate thecatalyst system. These impurities include water, oxygen, metalimpurities, etc. Typically, they are limited or eliminated beforeintroducing the reaction components into the vessel, but some scavengingcompound will normally be used in the polymerization process.

Typically, the scavenger will be an excess of the alkylated Lewis acidsneeded for activation, as described above, or will be knownorganometallic compounds such as the Group-13 organometallic compoundsof U.S. Pat. Nos. 5,153,157, 5,241,025, 5,767,587 and WO-A-91/09882,WO-A-94/03506, WO-A-93/14132, and that of WO 95/07941. Exemplarycompounds include triethyl aluminum, triethyl borane, triisobutylaluminum, methylalumoxane, isobutyl aluminumoxane, and tri-n-octylaluminum. Those scavenging compounds having bulky or C₆-C₂₀ linearhydrocarbyl substituents bound to the metal or metalloid center minimizeadverse scavenger interaction with the active catalyst. Examples includetriethylaluminum, but more preferably, bulky compounds such astriisobutylaluminum, triisoprenylaluminum, and long-chain linearalkyl-substituted aluminum compounds, such as tri-n-hexylaluminum,tri-n-octylaluminum, or tri-n-dodecylaluminum. Alumoxanes also may beused in scavenging amounts with other activation methods, e.g.,methylalumoxane and triisobutyl-aluminoxane. The amount of scavengingagent to be used with the invention Group 3-10 catalyst compounds isminimized to the amount that enhances activity and is omitted altogetherif the feeds and polymerization medium are pure enough.

Some catalyst embodiments are useful with polymerizable monomers.Suitable conditions are well known and include solution polymerization,slurry polymerization, and high-pressure polymerization. The inventioncatalyst is supported as described and will be particularly useful inthe known reactor operating modes employing fixed-bed, moving-bed,fluid-bed, slurry, or solution processes conducted in single, series, orparallel reactors.

The liquid processes comprise contacting olefin monomers with theabove-described catalyst system in a suitable diluent or solvent andallowing those monomers to react long enough to produce the inventioncopolymers. Both aliphatic and aromatic hydrocarbyl solvents aresuitable; aliphatic solvents such as cyclopentane or hexane are used insome embodiments. In bulk and slurry processes, catalysts are typicallybrought into contact with a liquid monomer slurry, such as propylene, ormonomer in a liquid diluent, such as ethylene in 1-hexene or 1-octene inn-butane. Representative reaction temperatures and pressure fordifferent embodiments are shown in Table I.

TABLE I Reaction Temperature and Reaction Pressure Embodiment ReactionTemperature in ° C. A ≦220 B ≧40 C ≦250 D ≧60 Reaction Pressure in bar E≦2500 F ≧0.1 G ≦500 H ≦1600 I ≧1.0 J ≧0.001

Linear polyethylene, including high- and ultra-high-molecular weightpolyethylenes, including both homo- and copolymers with other α-olefinmonomers, α-olefinic or non-conjugated diolefins, for example, C₃-C₂₀olefins, C₅-C₂₀ diolefins, C₇-C₂₀ vinyl aromatic monomers (such asstyrene) or C₅-C₂₀ cyclic olefins, are produced by adding ethylene, andoptionally one or more other monomers, to a reaction vessel, or morethan one vessel in parallel or series, under low pressure (typically <50bar), at a typical temperature of 40-250° C. These are placed togetherwith invention, supported catalysts suspended in a solvent or diluent,such as hexane or toluene. Cooling typically removes polymerizationheat. See, U.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670 and 5,405,922and 5,462,999, which are incorporated by reference for purposes of U.S.patent practice.

Semicrystalline polypropylenes can also be prepared with the inventionprocess, particularly those having 0.1-30 mol %, more preferably 7-25mol %, of ethylene or higher α-olefins. Polymers having sufficientethylene or other comonomer content to render them substantially solublein hexane are particularly suitable for preparation in stirred-tankreactors, tubular reactors, or any combination of stirred-tank ortubular reactors in parallel or series operation with the inventioncatalysts.

High molecular weight, low crystallinity ethylene-α-olefin elastomers(including ethylene-cyclic-olefin and ethylene-α-olefin-diolefin) can beprepared using invention catalysts under traditional solutionpolymerization processes or by introducing ethylene gas into a slurryusing α-olefin, cyclic olefin, or their mixtures with other compounds,polymerizable or not, as diluents for suspending invention catalysts.Typical ethylene pressures will be between 10 and 1000 psig (69-6895kPa), and the diluent temperature will typically be between 40 and 160°C. The process can be carried out in a stirred tank reactor, or morethan one operated in series or parallel. See the general disclosure ofU.S. Pat. No. 5,001,205 for general process conditions. See also,International Applications WO 96/33227 and WO 97/22639. All documentsare incorporated by reference for purposes of U.S. Patent Practice.

Some invention process embodiments are particularly applicable tosubstantially adiabatic, homogeneous solution polymerization. Adiabaticprocesses are those in which polymerization heat is accommodated byallowing a temperature rise in the reactor contents, here principallysolvent or diluent. Typically, in these processes, no internal coolingis absent and external cooling is unnecessary. The reactor outlet streamremoves reaction heat from the reactor. Cooling the solvent or monomerstream(s) before they enter these reactors improves productivity becauseit permits a greater polymerization exotherm. Thus, the catalyst,cocatalyst, and scavenger selections disclosed in this application canbe advantageously practiced in a continuous, solution process operatedat or above 140° C., above 150° C. or above 160° C., up to about 250° C.Typically, this process is conducted in an inert linear, cyclic orbranched aliphatic or aromatic solvent, at a pressure of from 10 to 200bar. These catalysts' provision of desirable polymer at elevatedtemperatures contributes to a greater exotherm, to high polymer contentin the reactor because of lower viscosity, to reduced energy consumptionin evaporating and recycling solvent, and to better monomer andcomonomer conversions. See, for example, U.S. Pat. No. 5,767,208, andco-pending U.S. application Ser. No. 09/261,637, filed Mar. 3, 1999 nowU.S. Pat. No. 6,291,609, and its equivalent WO 99/45041, all of whichare incorporated by reference for purposes of U.S. patent practice.

Ethylene-containing polymers for electrical devices are described moreparticularly in the literature. See, for example, U.S. Pat. Nos.5,246,783, 5,763,533, and International Publication WO 93/04486. Each ofthese polymers can be prepared in the manner described in the precedingparagraphs. Other olefinically-unsaturated monomers besides thosespecifically described in these documents may be polymerized using theinvention catalysts as well, for example, styrene, alkyl-substitutedstyrenes, isobutylene, and other geminally-disubstituted olefins,ethylidene, norbornene, norbornadiene, dicyclopentadiene, and otherolefinically-unsaturated monomers, including other cyclic olefins, suchas cyclopentene, norbornene, and alkyl-substituted norbornenes. See, forexample, U.S. Pat. Nos. 5,635,573, and 5,763,556. Additionally,α-olefinic macromonomers of 1000 mer units or more, may also becomonomers yielding branch-containing polymers. Each of the foregoingreferences are incorporated by reference for their relevant teachings.

Invention catalysts can function individually or can be mixed with othercatalyst to form a multi-component system. Monomer andcoordination-catalyst-blend selection yield polymer blends preparedunder conditions analogous to those using individual catalysts. Polymershaving increased MWD for improved processing and other traditionalbenefits available from polymers made with mixed catalyst systems canthus be achieved.

Blended polymer formation can be achieved ex situ through mechanicalblending or in situ through the use of mixed catalysts. Generally, insitu blending provides a more homogeneous product and allows one-stepblend production. In situ blending using mixed catalysts involvescombining more than one catalyst in the same reactor to simultaneouslyproduce multiple, distinct polymer products. This method requiresadditional catalyst synthesis. Moreover, the catalyst components must bematched for the polymer products they generate at specific conditionsand for their response to changes in polymerization conditions.

The following examples are presented to illustrate the foregoingdiscussion. All parts, proportions and percentages are by weight unlessotherwise indicated. All examples were carried out in dry, oxygen-freeenvironments and solvents. Although the examples may be directed tocertain embodiments of the present invention, they do not limit theinvention in any specific respect.

EXAMPLES

Materials

Toluene was purged with N₂ for 5 min, then dried over molecular sievesovernight. The toluene was poured down a basic-Al₂O₃ column before use.Tris(pentafluorophenyl)boron from Aldrich was dissolved in pentane andfiltered with a 0.45 μm filter. It was recrystallized from n-pentane ina freezer and vacuum dried at room temperature. Diethylaniline fromAldrich was dried over CaH₂ overnight and passed through a basic-Al₂O₃column before use. 1-hexene was dried over CaH₂ overnight and similarlypassed through a basic-Al₂O₃ column before use.

Example A

Cabosil was prepared by heating for 400° C. for 48 hrs followed byheating under vacuum at 200° C. for 6 hours. 0.54 g of the Cabosil wasadded to 30-40 mL dried toluene. 86 μL of prepared diethylaniline wasadded and stirred for 5 min. 0.2762 g of the recrystallizedtris(pentafluorophenyl)boron was dissolved in 3 ml toluene and thenslowly added to the silica-containing toluene solution. This mixture wasstirred for 30 min at room temperature and then allowed to settleovernight. The toluene layer was removed by pipette and the wet slurrywas dried under vacuum at room temperature to a produce a dry,free-flowing powder. The yield of silica-bound activator (SBA) was0.6555 g

Catalyst Preparation

263.88 mg of SBA was suspended in toluene and added to a toluenesolution of 90.7 mg of μ-diphenylmethylene (cyclopentadienyl)(fluorenyl) hafnium dimethyl. The mixture was stirred for 30 min at roomtemperature. The resulting supported catalyst was vacuum dried at roomtemperature.

Polymerization I

In a dry box, a portion of a small spatula full of the supportedcatalyst prepared above was placed in a dried 20-mL vial. Approximately5 mL of dried hexene-1 (passed through a basic-alumina column) was addedto the vial in liquid form. After a short period of time, the vialbecame hot and the liquid became notably viscous. On completion, thehexene-1 polymerized to sufficient molecular weight that the viscousmass flowed only sluggishly when the vial was turned upside down. A fewdays after polymerization, the nonporous, pinkish orange, supportedcatalyst settled out from the polymer solution, leaving a clear solutionbehind. Further fractionation can allow for substantial separation ofpolymer from catalyst residue. Subsequent analysis by LDMS and ToF-SIMSshowed insignificant labile anion presence, for both the separatedpolymer portion, and that with entrained residual catalyst. (Such use inthe suspension polymerization of polypropylene so that with or withoutcatalyst residue removal, effective grades for electrical gradepolypropylene products, for example, capacitor grade polypropylene canbe produced.)

Example B

Preparation of Cabosil 700

The silica was heated under a flow of dry nitrogen gas. A programmabletemperature controller was used to run the temperature profile shown inthe table below.

Temperature (° C.) Time (min)  25 to 105  48 105 to 160 132 160 to 700263 700 240 700 to 25  120

Example C

SBA-700 Preparation

2.669 g of Cabosil-700, prepared as in Example B, was suspended in 80 mLor toluene dried as described above. A solution of 0.106 μL DEA that hadbeen diluted in 0.9 mL toluene was added. This mixture was stirred for10 min at room temperature. A solution of 342 mg B(C6F5)3 dissolved in 5mL of toluene at room temperature was added. The product was filteredfrom solution and washed with 80 mL of toluene. The filtering/washingsteps were repeated two times. The product was vacuum dried at roomtemperature to a dry, free-flowing powder.

Example D

Catalyst Preparation

98.6 mg of SBA-700, produced in Example C, was slurried in 2.8 mLtoluene. 3.74 mL of 6 mMrac-dimethylsilylbis(3-methyl-4-phenyl-indenyl)Zirconium X₂ in toluenewas added to the SBA slurry. The mixture was stirred for 5 minutes. Theproduct was filtered and then vacuum dried at room temperature.

Example E

Polymerization II

0.3 mL of one-tenth diluted TIBAL (in toluene) was placed into a steamdried 2L reactor. 300 mL of liquid propylene was added to the reactor.The reactor was then heated to 60° C. 100 mg of the Catalyst of ExampleD was flushed into the reactor with 100 mL of propylene. Thepolymerization was run for 30 minutes. The reactor was cooled andvented. The polymerization yielded 43.3 g of dried polypropylene(catalyst activity 7.81×10⁶ g/mol-hr).

Comparative Examples and Experimental Data

Experimental data for LDMS and ToF-SIMS analyses of a series of EPcopolymers made using soluble rac-dimethylsilyl bis(indenyl) hafniumdimethyl and [dimethylanilinium]⁺[tetrakis(pentafluorophenyl)borate]⁻activator in a 1.0 L. continuous flow stirred tank reactor. All thepolymerizations were carried out using between 13 and 97 equivalents ofTIBAL. All polymerizations conducted at 110° C. with reactor residencetime of 12.8 to 15.0 min.

Polymerization Procedure (Single Reactor)

Polymerizations were carried out in one, one-liter stirred reactor withcontinuous flow of feeds to the system and continuous withdrawal ofproducts. The solvent was hexane. Monomers were ethylene and propylene,and were purified over beds of alumina and molecular sieves. All feedswere pumped into the reactors by metering pumps except for the ethylene(and hydrogen where applicable), which flowed as a gas under its ownpressure through a mass flow meter/controller. Circulating water througha reactor-cooling jacket controlled reactor temperature. The reactorswere maintained at a pressure in excess of the vapor pressure of thereactant mixture to keep the reactants in the liquid phase. The reactorswere operated liquid full.

Ethylene and propylene feeds were combined into one stream and thenmixed with a hexane stream that had been cooled to 0° C. A hexanesolution of triisobutyl aluminum scavenger was added to the combinedsolvent and monomer stream just before it entered the reactor to furtherreduce the concentration of any catalyst poisons. The catalystcomponents in solvent (usually toluene or toluene/hexane mixtures) wereseparately pumped to the reactor and, in most cases, activated in-linejust before the reactor, then the activated catalyst entered the reactorthrough a separate port outfitted with a dip tube to ensure adequatedistribution. The polymer/solvent/unconverted monomers and catalystsolution exit the first reactor through a pressure control valve thatreduced the pressure to atmospheric. This caused the unconvertedmonomers in the solution to flash into a vapor phase. The gas was ventedfrom the top of a vapor-liquid separator. The liquid phase, including,for the most part, polymer and solvent, flowed out the bottom of theseparator and was collected for polymer recovery. After removing a smallportion for determining cement concentration, stabilizer was added tothe polymer solution. The stabilized polymer was recovered from solutionby either steam stripping followed by vacuum drying, or by solventevaporation over heat and vacuum drying. Some comparative polymerizationdata are summarized in Table 1.

TABLE 1 Summary of EP Copolymers Analyzed Catalyst Polymer Wt. Avg. EffEst. wppm Scav/Cat Wt % MW Samples (g/g) of B(C₆F₅)₄ (mol/mol) C₂ (GPC)AA 17757 32 33 63.8 202,000 BB 11607 50 70.3 70.6 272,000 CC 24509 2213.2 58.6 166,000 DD  4810 120  97.1 72.9 288,000

All four samples were analyzed by LDMS and ToF-SIMS. In all cases theB(C₆F₅)₄ anion was readily detected. The match of peak intensities andmasses with those calculated for B(C₆F₅)₄ anion established itsidentity. All mass spectra were recorded using a PHI-Evans triple sectorelectrostatic analyzer time-of-flight mass spectrometer equipped withdual multichannel plate detector, ¹¹⁵In ion gun and nitrogen laser(λ=337 nm). The ion gun was operated at 15 keV and 600 pA. For LDMS,100-300 laser shots were used to acquire the spectrum. Laser power was˜10⁷ watts/cm². External and internal mass calibration was carried outusing a variety of known molecular standards and identities ofwell-established peaks in each mass spectrum.

Samples were prepared for analysis in two ways. In the first, a portionof the polymer was extracted with 5 mL of 90° C. toluene. Afterextraction for about 10 min. in a glass vial, approximately 1 μL of thesolution was deposited on a clean silicon wafer. In the second, aportion of polymer was cross-sectioned to expose the interior, and thefreshly exposed surface was analyzed directly.

Use of known masses and isotope distributions of relevant elements,below,

B 10.0129 (19.7%) 11.0093 (80.3%) C 12.0000 (98.89%) 13.00335 (1.11%) F18.9984 (100%)

with the stoichiometry of the [B(C₆F₅)₄]⁻ anion results in thecalculated values below.

B(C₆F₅)₄

Mass 677.98 678.97 679.98 680. Intensity, % 23 100 23 3

The negative ion LDMS mass spectrum of the pure [DMAH][B(C₆F₅)₄] saltprovided two major peaks, one at m/z=679 due to the intact B(C₆F₅)₄anion, and a second at 167 due to (C₆F₅)⁻. Along with peaks due toadditives and copolymer, a fingerprint at m/z=679 was observed. The 600to 700 region of this spectrum clearly showed that the peak nominally atm/z 679 in fact consisted of four peaks. These peaks are due to thecontributions of ¹⁰B (abundance 19.7%) and ¹³C (abundance 1.11%)isotopes to the mass spectrum of the Samples of Table 1. There was anexcellent match between the experimentally measured and calculatedintensities of the peaks due to the isotope contributions. Such anexcellent match between calculated and measured isotope patterns wasfound in all the m/z=679 spectra for the pure salt and the Samples. Inaddition to the isotope pattern match, the exact mass measured for eachof the four peaks in all the spectra also matched, within experimentalerror, those calculated for the B(C₆F₅)₄ anion.

In contrast, similar LDMS and ToF-SIMS analysis of isotacticpolypropylene prepared with a supported catalyst made in accordance withprocedures of reported Example 9 of U.S. Pat. No. 5,643,847, and havingthe support bound anion as described therein, did not contain signaturesof any B(C₆F₅)_(x) anions, where x specifically includes 3 or 4. Thus,using reference procedures, no evidence of the anion can be found in theinvention support bound cocatalysts. Yet, anion can be found in systemsthat do not use support bound cocatalysts. See, e.g. P. Brant, K.-J. Wu“Detection of B(C6F5)4 anions in polyethylenes made with ionicmetallocene catalysts.” Journal of Materials Science Letters 19 (2000)189-191.Therefore, the dielectric advantages of the supported catalystof this ionic catalyst supporting technique can be extended from thetaught gas phase and slurry polymerization processes to solutionpolymerization processes when using the support substrate materials ofthis application.

I claim:
 1. Sheathing for an electrical device or an electrical cablecomprising at least one polyolefin resin wherein the resin has beenprepared by contacting olefin monomers under essentially solution- orsupercritical-phase polymerization conditions with an activated, Group3-11 organometallic catalyst compound that has been activated with asupport-bound noncoordinating or weakly coordinating borate or aluminateanion, the support being finely divided fumed nonporous substrateparticles which are soluble or suspendable in the polymerizationsolvents or diluents.
 2. Sheathing according to claim 1 wherein thesupport comprises pyrogenic silica.
 3. Sheathing according to claim 1wherein the hydrocarbyl polymer chains are comprised of units derivedfrom olefins.
 4. Sheathing according to claim 3 wherein the hydrocarbylchains are soluble in aliphatic solvents.
 5. Sheathing according toclaim 1 wherein the organometallic catalyst compound is a Group 3-6metal compound containing a cyclopentadienyl-group.
 6. Sheathingaccording to claim 5 wherein the metal is titanium and the metalcompound contains only one pi-bound cyclopentadienyl group.
 7. Sheathingaccording to claim 5 wherein the metal compound comprises at least onebiscyclopentadienyl zirconium or hafnium compound.
 8. Sheathingaccording to claim 1 wherein the resin contains units derived fromethylene.
 9. Sheathing according to claim 8 wherein the resin is anethylene polymer comprising monomer units derived from at least oneC₃-C₁₂ olefins or non-conjugated diolefins.